Easy MCQ +4 / -1 PYQ · JEE Mains 2020

If the magnetic field in a plane electromagnetic wave is given by
$\overrightarrow B$ = 3 $\times$ 10-8 sin(1.6 $\times$ 103x + 48 $\times$ 1010t)$\widehat j$ T, then what will be expression for electric field ?

  1. A $\overrightarrow E$ = (9sin(1.6 $\times$ 10<sup>3</sup>x + 48 $\times$ 10<sup>10</sup>t)$\widehat k$ V/m) Correct answer
  2. B $\overrightarrow E$ = (60sin(1.6 $\times$ 10<sup>3</sup>x + 48 $\times$ 10<sup>10</sup>t)$\widehat k$ V/m)
  3. C $\overrightarrow E$ = (3 $\times$ 10<sup>-8</sup> sin(1.6 $\times$ 10<sup>3</sup>x + 48 $\times$ 10<sup>10</sup>t)$\widehat i$ V/m)
  4. D $\overrightarrow E$ = (3 $\times$ 10<sup>-8</sup> sin(1.6 $\times$ 10<sup>3</sup>x + 48 $\times$ 10<sup>10</sup>t)$\widehat j$ V/m)

Solution

Given $\overrightarrow B$ = 3 $\times$ 10<sup>-8</sup> sin(1.6 $\times$ 10<sup>3</sup>x + 48 $\times$ 10<sup>10</sup>t)$\widehat j$ T <br><br>We know, ${{{E_0}} \over {{B_0}}} = c$ <br><br>$\Rightarrow$ E<sub>0</sub> = (3 $\times$ 10<sup>-8</sup>) $\times$ (3 $\times$ 10<sup>-8</sup>) = 9 V/m <br><br>$\therefore$ $\overrightarrow E$ = (9sin(1.6 $\times$ 10<sup>3</sup>x + 48 $\times$ 10<sup>10</sup>t)$\widehat k$ V/m)

About this question

Subject: Physics · Chapter: Electromagnetic Waves · Topic: Maxwell's Equations

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